Approved for Little League play and meets Rule 1.06 which mandates a release style base. Unique two-part system features a dual safety design that allows the top to compress upon impact, then if the slide is too hard, it will disengage from the interlocking rubber "nubs" on the lower base plate. All rubber construction with a steel stancion that fits 1 1/2" female anchors. Anchors sold seperately. Official size 15" x 15" x 3". Available in Youth Set, Varsity Set, Double 1st Base, Youth Double 1st Base Set, and Varsity Double 1st Base Set.